reading partially works

src/GcLogger.cpp

@@ -33,6 +33,12 @@ int GcLogger::run() {
         string deviceVersion = device->getVersion();
         cout << "GMC Device version: " << deviceVersion << endl;
 
+        int cpm = device->getCPM();
+        cout << "CPM: " << cpm << endl;
+
+        float temperature = device->getTemperature();
+        cout << "Temperature: " << temperature << endl;
+
         device->close();
         return EXIT_SUCCESS;
     }

src/GmcDevice.cpp

@@ -36,7 +36,9 @@ int GmcDevice::getCPM() {
     string result;
 
     if(device->serialWrite(cmd) == cmd.length()) {
-        device->serialRead(result, 2); // cpm result has size 2
+        result = device->serialRead(2); // cpm result has size 2
+    } else {
+        cout << "Failed to send command to device!" << endl;
     }
 
     return result[0] * 256 + result[1];
@@ -52,7 +54,9 @@ float GmcDevice::getTemperature() {
     string result;
 
     if(device->serialWrite(cmd) == cmd.length()) {
-        device->serialRead(result, 4); // temp result has size 4
+        result = device->serialRead(4); // temp result has size 4
+    } else {
+        cout << "Failed to send command to device!" << endl;
     }
 
     int sign =  result[2] == 0 ? 1 : -1;
@@ -72,7 +76,9 @@ string GmcDevice::getVersion() {
     string result;
 
     if(device->serialWrite(cmd) == cmd.length()) {
-        device->serialRead(result, 14); // version result has size 14
+        result = device->serialRead(14); // version result has size 14
+    } else {
+        cout << "Failed to send command to device!" << endl;
     }
 
     return result;
@@ -84,6 +90,15 @@ bool GmcDevice::setHeartbeatOff() {
         return false;
     }
 
+    string cmd = "<HEARTBEAT0>>";
+    string result;
+
+    if(device->serialWrite(cmd) == cmd.length()) {
+        return device->clearInput(100); // clear 100 chars
+    } else {
+        cout << "Failed to send command to device!" << endl;
+    }
+
     return false;
 }
 

src/SerialPort.cpp

@@ -60,8 +60,15 @@ SerialPort::~SerialPort() {
     serialClose();
 }
 
-int SerialPort::serialRead(string buffer, int length) {
-    return read(fd, buffer.data(), length);
+string SerialPort::serialRead(int length) {
+    char *buf = (char *) calloc(length + 1, sizeof(char));
+
+    read(fd, buf, length);
+
+    string result(buf);
+    free(buf);
+
+    return result;
 }
 
 int SerialPort::serialWrite(const string &data) {

src/SerialPort.h

@@ -30,7 +30,7 @@ public:
     bool isOpen();
     bool serialClose();
 
-    int serialRead(string, int);
+    string serialRead(int);
     int serialWrite(const string&);
     bool clearInput(int);
 };